To disable the key-in-ignition chime:
Remove the column shroud - 3 screws underneath, and a bit of force to separate the top and bottom shell covers.
There is a 4 way connector cable tied to the rear of the ignition lock assy. It is vertical, with 2 purple, one purple/blue, and one purple/white coming out the top. On the bottom, there is a black and a white wire - the wiring book shows the white is feed into the switch, the purple/white is output going to MFU. If you cut the white wire, the chime will go away. There is room to reconnect the wire if needed later.
If you wat to go for the jugular and also disable the lights-on chime:
Remove the fuse box cover under the steering column and undo the two bolts which secure the fuse-box in place. Pull it out as far as it will come without pulling out any
wires. At the back of the fuse-box asembly, under a plastic cover, you'll find the MFU circuit. Open the cover and find on the circuit board a small buzzer (a cylinder shaped bit with a small hole in the middle. Block the hole and the buzzer will become almost inaudible, or desolder the connections and remove it altogether.
Another annoying feature which you are likely to discover travelling over bumps, is the hazard lights coming on when the vehicle jumps on an obstacle. This feature seems to be hard-wired into the MFU circuit and not so easy to disable. I'm still trying to find out how to do it.
Hope it helps,